Office



(No Model.)

G. M. QUEENS. P111GT10N`0LUTGE F011 1100K DRILLS. v

No. 317,113. Patented May 5, 1885.

N.- f@ f 7@ N 1. f yf a IUNTED STATES PATENT OFFICE.

GEORGE M. GITHENS, OF BROOKLYN, N'EV YORK.

FRICTIOYN-CLUTCH SPECIFICATION forming part f Letters Patent No. 317,113, dated May 5,

' Application filed January 5, 1885. (No model.)

To all whom it may concern:

Be it known that I, GEORGE M. GrrHENs, of Brooklyn, inthe county of Kings and State of New York, have invented an y Improvement in Friction Clutches for Rock- Drills, &c., of which the following is a speciication. I

Friction-clutches have been applied to th ried bar that serves to rotate the piston and drill in steam and air rock-drilling machines. The rollers that are used between the camhead and the interior'of a containing-cylinder wedge tight and prevent the rifle-bar turning in one direction, and release it andl allow it to move freely in the other direction; but such rollers are liable either to stick fast and hold the parts immovable or else to wear `flat in sections and become inoperative.

In rock-drills there is a constant tendency to rotate the drill in one direction or the other, because the rock at the bottom of the hole is not flat and the cutting-edge of the drill is at the end of a wedge-shaped part of the metal. Sometimes the wedge-shaped cuttingedge, in striking against the rock, glances and sets the drill and piston in rotation violently. At other times the drill end penetrates a seam and receives thereby a powerful turning or twisting movement. If the clamp that holds the riflebar allows the parts -to turn in one direction, but is too powerful and prevents the drill and piston turning in the other direction, injury is liable frequently to be done to the drill or to the clamp or to the piston-rod.

The object of my present invention is to prevent the parts wearing in such a manner as to become inoperative, to hold the rifle bar or shaft with sufficient force lto cause it to turn the piston, rod, and drill when moving in one direction, and to loosen the rifle-bar so that it may be free to turn by the action of the piston when moving in the other direction, and to allow the clutch itself to turn when an undue torsion is applied to the drill, and thereby prevent injury to any of the parts by allowing them to turn and yield when the drill may strike a powerful glancing blow.

In the drawings, Figure 1 is a longitudinal section of part of the rock-drill cylinder and heads and an elevation of the rifle-bar. Fig.

FOR ROCK-DRILLS.

2 is an end view of the cams, clamps, and holder. Fig. 8 is a section, and Fig.` 4an elevation, of the cams and holder arranged in a modified form; and Fig. 5V is a section of the cams in different form from that shown in Figs. 1 and 3.

The cylinder 'a, feedingscrew b, and piston c are of ordinary character, and the rifle or feed bar d passes into the piston, as usual.

The cylinder-head e is adapted to receive the cap f, and the two are secured by thebolts e2 or bythe bolts of the cylinder. This head and cap are recessed to receive the cam-head h of the rifle-bar d and the clamps 7c, that hold the cams. 1

The cams 7L are two or three ,in number. Inl Figs. 1 and 2 they are represented as sections of volutes and extend outwardly. In Figs.A 3'

and 4 they are shown as concentric inclines. The cams act against clamp-pieces 7c. If there are volute-cams, there must be a clamp for each cam; but with the concentric inclines, Figs. 3 and 4, the inclines or cams act against similar inclines or cam -surfaces -upon the clamps. If the exterior surfaces of the clamps 7c, Figs. 1 and 2, are cylindrical, as shown in Fig. 5, or. if the upper surface of the clamp, Figs. 3 and 4, is fiat and withoutthe annular rib, the device is liable not to be fully operative, because the action of the cams upon the clamps will either revolve the clamps in either direction or else the cams may wedge the clamps immovably, or so nearly so that the parts will not operate promptly or will be injured.

I find that the power required to hold the clamps from rotating must be sufficiently great to prevent them turning under the ordinary outward pressure of the cams, so that the clamps will remainstationary and hold the cams when the parts are being turned in one direction, and will freethemselves and turn freely in the other direction. To accomplish this object Iproportion the inclined surfaces ofthe cams so as to hold with the required power, and I prefer to make use of a wedge-acting holder for the clamps. Vhen the clamp is in the form of a disk, Figs. 3 and 4, there is a V or wedge groove and a similar and the groove in the clamp, or the reverse. Vhen the clamps are in the form shown in Figs. l and 2, the holder is in the form of either a single or double conical edge to the clamp and a similar-shaped recess to the heads. In both cases the action ofthe cams is to force the clamps into the wedge-acting holders, and Wedge the same With sufficient rmness to hold the clamp in order that the cams may separate upon the reverse movement, in consequence of the clamps remaining stationary as the cams turn away from them, thus releasing the parts and allowing the reverse movement before named; but the parts will yield and turn under an unusual strain Without njury or breakage.

At p is a screw-plug to an oil-hole, and at q there is a hole in the cam, with branches to supply the lubricant to the surfaces of the cams. Y f f The holder that applies friction to the surfaces of the clamp or clamps is of a greater diameter than the cams upon the ride-bars hence there is a greater friction against the exterior of the clamps to hold them than there is of the cams as they act against the clamps to move them in either direction; hence by proportioning the angles or inclinations of the contactsurfaces the clamps are held with sufficient frictional force to cause the rotation of the pisfon and drill as the piston moves forward over the ride-bar; butunusualstrainin this direction will cause the clamps to slide upon their contact-surfaces by the rotative power of the piston and drill. In the other direction the cams turn away from the clamps,while the latter are held by superior friction, and then all the parts rotate freely.

I claim as my invention-- l. The combination, With the cams and the shaft or rifie-bar to which they are connected, of the clamps that are moved by and revolve With the cams, and the holder for the exterior surface of the clamps,substantially as set forth. 

